After re-running Roots of Terror in HoT's storyling, I came across 2 new bugs (+ additional bugs):
Bug 1. In order to get the achievement points for 'Choose the left path', I had to take the right path double times.
**Bug 2. ** After defeating 'The Creature' at the very end, if you run ahead into the Chak pit during the dialogue with Magister Humli, and start to kill Chak, and then try to speak to Braham again after the dialogue with Magister Humli, you cannot finish Roots of Terror.
Additional bugs (from the Wiki. Why are these note fixed yet? Do your developers read any of the bug notes for each storyline part, Anet?):
Bug 3. Sometimes Chak in the Chak Pit spawn behind the walls making the "Chak Killer—Master" achievement impossible to achieve.
Bug 4. Dying during the Chak Blitzer fight will often bug out Braham making it impossible to progress the mission.
Here is a fun fact regarding the sound of Chak in Roots of Terror:
If you kill all Chak in the pit at the very end, the sound of Chak can still be heard all around instead of each Chak having their own sound. Otherwise, killing the last Chak should leave the area quiet. My guess is this may be the case in other parts of the game with Chak.
I hope these bugs get fixed so anyone new to HoT doesn't have to experience them. Cheers.